Play day in a crawlspace!
I've had folks tell me that you couldn't pay them enough to go into a crawlspace. I usually don't have that problem. Today, though, I did it for free.
Why? A) Because it was a 120 year old building that I knew I'd end up referring to an engineer; B) it was a 120 year old building that was totally cool to check out. Went from one basement, all the way through to the other basement addition, climbed out on a piece of abandoned equipment and had to climb up the old elevator shaft on a rickety old homemade wood ladder wired onto some old conduit.